Playback stutters when Selection Follows Play Head

When I enable "Selection Follows Play Head" the playback stutters and is sluggish as to be unusable.
It is a very simple timeline, just on clip on track 1 and a bunch of Title FX on track 2
Resolve 14.3, Win 10

Which version of Resolve? What OS? What hardware (CPU, GPU, RAM, I/O)? What type of camera source files?

It works for me with 4K R3D files,4K CinemaDNG, and 4k & 2K ProRes 444 files under Mac OSX 10.12.6 and Resolve 14.3 on a 12-core Trashcan Mac.

Resolve 14.3.0.014
Windows 10 Pro
64 GB Ram
i7 6 core 4GHz
GTX1080TI

V1 has one clip 1920x1080p24 H264 9Mbps
V2 has about 200 title FX (subtitles)
one audio track mp3

Yes, I noticed this problem a couple of versions ago.
I can confirm it was a matter of source material: h264 & mp3

Seems to be less of a problem for me in latest version.